The full-scale, $10 billion version of a proposed fusion power test-bed appears to be defunct. The troubled International Thermonuclear Experimental Reactor (ITER) received little support from U.S. fusion experts at a recent meeting in Madison, Wisconsin, to discuss the next step for fusion, according to a news report in tomorrow's Science[2]. And in a final blow, a representative from Japan, until now the project's staunchest supporter, floated designs for a smaller and less ambitious machine--a roughly half-price version that has been dubbed an "ITER Lite."

As originally envisioned, ITER would be a gigantic tokamak--a donut-shaped device threaded with magnetic field lines that would confine hot, ionized gas, or plasma. To be built by the United States, Japan, Russia, and Europe, the 16-meter device would ignite a self-sustaining thermonuclear fire, although some scientists have raised doubts about whether ITER would work as advertised. Now Japan's economic problems have led it to request a 3-year delay in any decision on whether to build ITER, and the Department of Energy's budget request for 1999 has slashed U.S. funding for ITER by almost 75%, to $15 million. "Everyone recognizes that [the full-scale machine] just can't be mounted," says David Baldwin, senior vice president for the fusion group at General Atomics in San Diego.

As a result, fusion scientists are now focusing on scaled-down versions like Japan's ITER Lite, roughly 30% smaller than the original. Presented by Mitsuru Kikuchi of the Japan Atomic Energy Research Institute, the design would settle for a fusion output well short of ignition. The lower fusion yield would, among other things, allow the voluminous shielding that protects the ultracold superconducting magnets to be pared down.

Beleaguered ITER leaders say they welcome such alternatives. Says Charles Baker, the ITER U.S. Home Team Leader, "I think something in the 50% range ... may open up the possibility of [actual construction] happening." But other researchers complain that the smaller ITER relies heavily on simply scaling up current knowledge rather than looking for new ways to reach fusion. Mark Haynes, vice president for Washington operations at General Atomics, fears that ITER Lite may be a dead end politically as well: "My view is that most people in Congress are not going to view a half-price ITER substantially more favorably than a full-price ITER."